General expression profiles of human native odontoblasts and pulp-derived cultured odontoblast-like cells are similar but reveal differential neuropeptide expression levels.
OBJECTIVE
Odontoblasts play a central role during the dentin formation by organic matrix production and mineralisation. Recently, suitable in vitro techniques for studying mature primary odontoblasts and the newly differentiated odontoblasts have been developed. Firstly, the gene expression profiles of native and cultured odontoblasts were compared at large-scale to investigate the similarities and differences between the samples. Secondly, differential expression levels of the genes encoding neuronal proteins were analyzed to study odontoblasts sensory function.


METHODS
Microarray analysis was performed to mature native and cultured pulp-derived odontoblast-like cells to compare their transcriptome. Then, the probes positive only in one sample were divided into gene ontology categories. Expression levels of selected neuronal proteins were further studied with quantitative PCR, and at the protein level by immunofluorescence of mature and newly differentiated odontoblasts in developing tooth.


RESULTS
Remarkable similarities between the general and neuronal protein gene expression profiles were observed. Higher cortistatin, galanin, somatostatin receptor 1 (SSTR1) and tyrosine phosphatase receptor type Z1 (PTPRZ1) expression was detected in native than in cultured odontoblast at the mRNA level. Pronociceptin was more abundantly expressed in cultured than in native odontoblasts. Immunofluorescence of mature and newly differentiated odontoblasts on human tooth germs confirmed the results.


CONCLUSIONS
Cultured odontoblasts used in this study have similar general gene expression pattern to native odontoblasts, and therefore offer a valuable tool for the in vitro odontoblast studies. The expression of PTPRZ1 and galanin, which participate in sensory signal transduction, supports the previously suggested role of odontoblasts as sensory cells.
Pääkkönen
Virve
V
Institute of Dentistry, 90014 University of Oulu, Oulu, Finland.
Bleicher
Françoise
F
Carrouel
Florence
F
Vuoristo
Jussi T
JT
Salo
Tuula
T
Wappler
Ilka
I
Couble
Marie-Lise
ML
Magloire
Henry
H
Peters
Heiko
H
Tjäderhane
Leo
L
D000293:Adolescent; D000328:Adult; D002478:Cells, Cultured; D003782:Dental Pulp / Q000378:metabolism*; D005260:Female; D019004:Galanin / Q000235:genetics; D020869:Gene Expression Profiling; D006801:Humans; D008297:Male; D046228:Microarray Analysis; D009479:Neuropeptides / Q000235:genetics* / Q000378:metabolism; D009804:Odontoblasts / Q000378:metabolism*; D011498:Protein Precursors / Q000235:genetics; D054633:Receptor-Like Protein Tyrosine Phosphatases, Class 5 / Q000235:genetics; D011957:Receptors, Opioid / Q000235:genetics; D017481:Receptors, Somatostatin / Q000235:genetics; D015398:Signal Transduction; D055815:Young Adult
C056567:GAL protein, human; D009479:Neuropeptides; D011498:Protein Precursors; D011957:Receptors, Opioid; D017481:Receptors, Somatostatin; C099323:cortistatin; C119224:pronociceptin; C101130:somatostatin receptor type 1; D019004:Galanin; C516895:PTPRZ1 protein, human; D054633:Receptor-Like Protein Tyrosine Phosphatases, Class 5